Double-walled furnace.



' PATENTED 00T. 3,1905.

L. G. LBPPER.

DOUBLE WALLED PURNAGE.

APPLIOATION FILED SEPT. 22. 1903.

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i l l UNITED STATES PATENT OEEIQE.

LOUIS GEORG LEFFER, OF LINDENTHAL-OOLOGNE, GERMANY, ASSIGNOR TO ERNST HAUSMAN N, OF LINDENTHAL-OOLOGNE, GERMANY.

DOUBLE-WALLED FURNACE.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed September 22, 1903.` Serial No. 174,201.

I To @ZZ whom it may concern,.-

Beit known that I, Louis GEORG LEFFER, engineer, of 95 Bachemerstrasse, Lindenthal- Cologne, in the Empire of Germany, have invented certain new and useful Improvements in and Connected with Double-Walled Furnaces; and I do hereby declare that the following is a full, clear, and exact description of the same.

In the usual form of double-walled furnaces the air enters at the rear of the casing and disperses throughout the hollow air-space in the casing and escapes therefrom through noz- Zles or openings in the inner side to the under side of the grate.

The object of the present invention is to improve the construction or arrangement of the double casing in order to obtain a maximum warming' of the air by the heat radiated from the furnace and to avoid the warping' which is unavoidable with the ordinary fiatplate double-walled furnaces on account of the great heat.

The invention consists in arranging the double-walled furnace so that the air enters at the rear near the top, passes downwardly through a channel, divides at the lower end of the said channel, and then disperses upward about the rear wall, and further passes through openings near to the top into the side walls, the inner plate of which is inclined and formed of corrugated metal, the air so warmed escaping through openings in the lower parts of the inside walls to the grate.

In the accompanying drawings, Figure 1 is a vertical sectional view of afurnace and oasing constructed in accordance with this invention. Fig. 2 is a horizontal sectional view taken on the line 2 2 of Fig. l. Fig. 3 is a transverse sectional view on the line 3 3 of Fig. Q. Fig. 4 is a perspective view of the casing, the outer walls being partly broken away to show the interior construction.

In carrying out the invention according to one modification, as illustrated, an iron casing a, sustaining the furnace, is constructed of rectangular form in plan. The walls of the casing are double, except at the front, which may be single and form the door. Air is admitted at the rear through an opening preferably circular, situated near the top. It is led down inside the back casing-wall in a suitable channel c, formed, for instance, by

two partitions cl, which may be parallel, but are preferably diverging toward the bottom, as shown. The partitions Z terminate a little short of the bottom in order to form openings through which the air can pass, as shown by arrows, and disperse about the remainder of the back wall, from which it is led by openings e at the top corners into the hollow side walls.

The inner walls f of the hollow side walls are made corrugated and are also inclined, the space or width of the hollow walls increasing toward the bottom. The corrugated walls have suitable openings g arranged near the bottom to allow the now heated air to pass below the grate into the iire.

It will be understood that the space formed below the grate is tapered. This arrangement serves, in combination with the large surface of the corrugated iron of the inside walls f, to warm the air of the blast intensely. At the same time the corrugated iron allows of expansion and contraction; so the warping is avoided and a long life of the furnace secured.

The casing, besides heating the air and supporting the walls of the furnace, also constitutes an ash-pit.

What I claim as my invention` and desire to secure by Letters Patent, is

l. The combination with a furnace embodying walls and a grate, of a double-walled casing located beneath the walls and the grate of the furnace and supporting the former and constituting an ash-pit for the latter, the back of the casing being provided at the top with an air-inlet and having passages extending from the top to the bottom of the said back and discharging into the spaces between the walls of the sides of the casing, said sides having outlets at the bottom communicating with the space inclosed by the casing.

2. The combination with a furnace embodying walls and a grate, of a double-walled casing located beneath the walls and the grate of the furnace and supporting the former and constituting an ash-pit for the latter, the back of the casing being provided at the top with an air-inlet and having partitions located at opposite sides of the inlet and extending downward from the top of the casing and terminating short of the bottom thereof to form intermediate and side passages, the sides of the casing communicating at the top with the side inclined and provided at the bottom with outlets communicating with the interior of the casing, and partitions located at opposite sides of the air-outlet and forming air-passages, the latter being` in communication with the spaces between the walls oi' the sides.

In Witness whereof I have hereunto set my hand in presence of two witnesses.

LUUIS GEORG LEFFER. Vitnesses:

GUSTAV ELSNER, GoH SoHoLz. 

